For quick reverb in FL Studio, I’ll usually throw Fruity Reeverb 2 onto a mixer track, alter the “wet” parameter, and unless you’re going for a very specific reverb style, that is usually all you need to create a great reverb effect.
It also comes with a huge amount of FX, and they sound extremely good right out the box. The synths, such as my personal favourite: Sytrus, are highly effective for producing a huge array of sounds for any genre, and come with huge libraries of patches and presets for immediate inspiration. FL Studios collection of features is unbelievably impressive.